The present invention relates to a circuit module having a high-voltage element and a connector connected to the high-voltage element, and also to an electronic apparatus, such as a portable computer, which incorporates the circuit module.
Portable electronic apparatuses, typified by portable computers, comprises a main body and a display unit. The display unit is supported by the main body. The display unit comprises a box-shaped housing, a flat liquid crystal display, and an FL inverter. The housing has an opening in the front. Both the display and the FL inverter are provided in the housing. The liquid crystal display has a screen to displaying information, such as characters and images. The screen is exposed outside through the opening of the housing. The FL inverter is designed to drive the back light incorporated in the liquid crystal display. The FL inverter is an elongate component, which extends horizontally in the lower part of the housing or vertically in the left or right part of the housing. The FL inverter is electrically connected to the back light by a cable. The cable has a cable connector at its distal end.
Recently it is increasingly demanded that portable computers be thinner and lighter. It is also demanded that portable computer have a large, high-resolution screen for displaying information that is easy to perceive visually. The larger the screen, the larger the liquid crystal display. The display will occupy almost all inner space of the housing unless the size of the housing of the display unit is proportionally increased. No space will be hardly provided to accommodate the FL inverter. If so, it is necessary to make the FL inverter more slender and more compact.
A conventional FL inverter of ordinary type is a circuit module. It comprises an elongate circuit board and various circuit components mounted on the circuit board. Among the circuit components are a transformer and a connector. The transformer and the connector are arranged on one end section of the circuit board. The transformer has a first output terminal for outputting a reference voltage and a second output terminal for outputting a voltage higher than the reference voltage. The connector has a first connection terminal and a second connection terminal. The first and second connection terminals extend parallel and are spaced part. The cable connector provided at the distal end of the above-mentioned cable is removably connected to both connection terminals of the connector.
The circuit board has a pair of wiring patterns. The wiring patterns are located between the transformer and the connector. They extend parallel and spaced apart from each other. The first writing pattern has a first end soldered to the first output terminal, and a second end soldered to the first connection terminal. The second writing pattern has a first end soldered to the second output terminal, and a second end soldered to the second connection terminal. Thus, the wiring patterns electrically connect the connector to the transformer.
In the FL inverter thus structured, a high voltage is applied to the second wiring pattern that is connected to the second output terminal. The wiring patterns must be spaced apart sufficiently in order to prevent discharge between them. The width of the circuit board is inevitably large. Consequently, the FL inverter cannot be so slender or compact as is recently demanded.
Hitherto, a slit is made in that part of the circuit board which lies between the wiring patterns, thereby to prevent discharge between the wiring patterns. The slit is less wide than the distance by which the wiring patterns should be spaced apart to prevent discharge. Hence, the wiring patterns can be positioned closer to each other than in the case where the circuit board has no slits, and the circuit board can be made narrow and compact.
However, the circuit board cannot have a sufficient strength since the slit extends along the entire length of both wiring patterns. If the circuit board is pushed while being secured to the housing of the display unit, it may be bent at the part having the slit. If the circuit board is bent, the solder junctions of the wiring patterns and the output terminals and connection terminals may have cracks, or the output terminals and connection terminals may peel off the wiring patterns. In either case, the electrical connection between each wiring pattern and the terminals will be impaired. Hence, much cares must be taken to secure the to the housing of the display unit.
In the conventional FL inverter, the wiring patterns mounted on the circuit board are exposed. It is therefore necessary to attach an insulator made of synthetic resin to the circuit board after soldering the transformer and the connectors to the board, thereby to cover all exposed parts of the wiring patterns, including the sides of the patterns. Inevitably, the number of steps of assembling the FL inverter will increase.